The invention relates to a two-stage clutch for separable connection of an input shaft to at least one output shaft, in particular a booster clutch for a motorcycle.
For many applications it is desired that a clutch be able to be operated by hand. That is, the forces for engaging and disengaging the clutch must be small enough so that they are controllable without exerting additional mechanical force. But, specifically, when transmitting high torques and/or when little construction space is available for a complex lever arrangement, the necessary clamping forces and low operating forces cannot be reconciled. To solve this problem, so-called booster clutches are known, in which a main clutch is controlled by a booster clutch. The forces for clamping are produced by the torque which is present to be transmitted, for example, by means of a ramp system which converts part of the available torque to a clamping force. But, because-especially in motor vehicles—a torque is to be transmitted not only in one direction but also in the opposite direction, for example, in deceleration mode, the ramp system must be operable in two opposite engaging positions. So that no jerky changeover from the first position to the second position of the ramp system occurs when changing between the two operating modes of the clutch, a torque sensor is provided. The latter ensures that when there is a decrease in the currently present torque in the one direction, the present clamping force, and thus the relative position of the ramp elements of the ramp system, is gradually adapted, that is, gradually disengaged. Such a booster clutch can thus be utilized like a conventional clutch. Of course, the construction of such a booster clutch is very complex, and furthermore is too expensive for many applications.